1. Field of the Invention
The invention relates to a process for coating electrically conductive substrates, in which
(1) the electrically conductive substrate is immersed in an aqueous electrodeposition paint PA1 (2) the substrate is connected as the cathode PA1 (3) a film is deposited on the substrate by direct current PA1 (4) the coated substrate is removed from the electrodeposition paint and PA1 (5) the deposited paint film is baked. PA1 a) optionally modified polyepoxides and PA1 b) amines. PA1 (i) a diepoxide compound or a mixture of diepoxide compounds having an epoxy equivalent weight of less than 2,000 with PA1 (ii) a compound which contains a phenol or thiol group and which reacts monofunctionally with epoxide groups under the given reaction conditions or a mixture of such compounds, PA1 (a) Compounds containing carboxyl groups, such as saturated or unsaturated monocarboxylic acids (for example benzoic acid, linseed oil fatty acid, 2-ethylhexanoic acid and versatic acid), aliphatic, cycloaliphatic and/or aromatic dicarboxylic acids of variable chain length (for example adipic acid, sebacic acid, isophthalic acid or dimeric fatty acids), hydroxyalkyl carboxylic acids (for example lactic acid or dimethylolpropionic acid) and also polyesters containing carboxyl groups or PA1 (b) compounds containing amino groups, such as diethylamine or ethylhexylamine, or diamines having secondary amino groups, for example N,N'-dialkylalkylenediamines, such as dimethylethylenediamine, N,N'-dialkylpolyoxyalkyleneamines, such as N,N'-dimethylpolyoxypropylenediamine, cyanoalkylated alkylenediamines, such as bis-N,N'-cyanoethylethylenediamine, cyanoalkylated polyoxyalkyleneamines, such as bis-N,N'-cyanoethylpolyoxypropylenediamine, polyaminoamides, such as, for example, versamides, in particular reaction products formed from diamines (for example hexamethylenediamine) and containing terminal amino groups, polycarboxylic acids, in particular dimeric fatty acids, and monocarboxylic acids, in particular fatty acids, or the reaction product of one mole of diaminohexane with two moles of monoglycidyl ether or monoglycidyl ester, in particular glycidyl esters of .alpha.-branched fatty acids, such as versatic acid, or PA1 (c) compounds containing hydroxyl groups, such as neopentylglycol, bis-ethoxylated neopentylglycol, neopentylglycol hydroxypivalate, dimethylhydantoin-N,N'diethanol, 1,6-hexanediol, 2,5-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, 1,1-isopropylidene-bis-(p-phenoxy)-2-propanol, trimethylolpropane or pentaerythritol, or amino alcohols, such as triethanolamine or methyldiethanolamine, or alkyl kerimines containing hydroxyl groups, such as aminomethyl-1,3-propanediol methyl isobutyl ketimine or tris-(hydroxymethyl)-aminomethane cyclohexanone ketimine, and also polyglycol ethers, polyester-polyols, polyether-polyols, polycaprolactone-polyols or polycaprolactam-polyols of varying functionality and molecular weights or PA1 (d) saturated or unsaturated methyl esters of fatty acids which are transesterified in the presence of sodium methylate with hydroxyl groups of the epoxy resins. PA1 R.sup.1 =R.sup.2 0--C0--CH.sub.2 --, R.sup.3 --CHOH--CH.sub.2 --R.sup.4 --CHOR.sup.5 CHOH--CH.sub.2 -- PA1 R.sup.2 =alkyl PA1 R.sup.3 =H, alkyl, R.sup.6 0--CH--.sub.2 or R.sup.6 --CO--O--CH.sub.2 -- PA1 R.sup.4 =H or alkyl PA1 R.sup.5 =H, alkyl or aryl PA1 R.sup.6 =alkyl, cycloalkyl or aryl
The invention also relates to an aqueous, cathodically depositable electrodeposition paint.
2. Description of the Related Art
The cathodic electrocoating process described above is known (cf., for example, German Offenlegungsschrift 3,518,732, German Offenlegungsschrift 3,518,770, EP-A 4,090, EP-A 12,463 and EP-A 262,069) and is employed, in particular, for priming automobile bodies.